Ami hasn't really proved to me she'd get physical yet. Chika has, and Ayane is done with Kirin's shit as well as knows some karate, and knows about the loop, so I wouldn't be surprised if she snaps. Also Yeah, Yumi would 100% back Chika up.
I do think the Class wouldn't be that shocked, however they would feel like crap and if enough of them start being Anti-Kirin, it might come down to a Sensei having to cut ties with her or actually losing them scenario, which might spark a whole bunch more drama between the class. Knowing he's with other girls is one thing, but having it rubbed in by the class hussy can not be good for their already damaged psyches. Not to mention it'd damage Kirin's friendship with Noriko, and likely Miku as well if Makoto is hurt enough. So, it'd be a shitshow.
Keep in mind that Nodoka doesn't let people who hurt Futaba off that easy either. This would undoubtedly hurt Futaba, so Kirin could become her next target, especially if she continues trying to hurt the class using Sensei.
Kirin also might threaten to rat Sensei out about screwing his students if he actually does try to dump her. I get very "If I'm going down, I'll take you all with me" vibes from her. Which would probably then get Maya involved because she would refuse to lose Sensei. In the end, Ayane and Maya might be burying a body.
Overall, I'm concerned like Pareidolia, the 3rd god.